text: import sqlite3
  
  class MySum:
      def __init__(self):
          self.count = 0
  
      def step(self, value):
          self.count += value
  
      def finalize(self):
          return self.count
  
  con = sqlite3.connect(":memory:")
  con.create_aggregate("mysum", 1, MySum)
  cur = con.cursor()
  cur.execute("create table test(i)")
  cur.execute("insert into test(i) values (1)")
  cur.execute("insert into test(i) values (2)")
  cur.execute("select mysum(i) from test")
  print(cur.fetchone()[0])
  